If you have ever wanted to build your own portable speaker or add sound to a custom arcade cabinet, you have likely come across a tiny green board labeled

| Symptom | Likely Cause | Solution | |---------|---------------|----------| | No sound, IC hot | Short on speaker output | Check that neither speaker wire touches ground or VCC | | Distorted sound at low volume | Input voltage too low (<2.5V) or audio source clipping | Use stable 5V supply; reduce source volume | | Popping noise on power-up | Lack of output RC snubber | Add 1µF capacitor in parallel with each speaker (optional) | | One channel silent | Broken PCB trace or bad IC | Swap L and R inputs to test; check solder joints | | Amplifier shuts down intermittently | Overheating or supply droop | Add heatsink or reduce volume; check power supply current rating (needs at least 1A for 2×3W) |

| Parameter | Value | |-----------|-------| | | PAM8403 (most common) or NS4150 (less common) | | Amplifier Class | Class-D (filterless) | | Output Power | 3W per channel into 4Ω load (at 5V, 10% THD) | | Typical Efficiency | 85-90% | | Supply Voltage | 2.5V – 5.5V DC | | Quiescent Current | ~8mA (no load) | | Shutdown Current | <1µA | | Load Impedance | 4Ω – 8Ω | | THD+N | 0.1% (1W, 4Ω, 5V) | | Signal-to-Noise Ratio | 87dB | | Channel Separation | 75dB | | Operating Temperature | -40°C to +85°C | | PCB Size | Approx. 23mm x 18mm |

| Parameter | Symbol | Min | Max | Unit | | :--- | :--- | :--- | :--- | :--- | | Supply Voltage | Vcc | - | 18 | V DC | | Output Peak Current | Io | - | 2 | A | | Power Dissipation (Tc=70°C) | Ptot | - | 20 | W | | Operating Junction Temp | Tj | -40 | 150 | °C | | Storage Temperature | Tstg | -55 | 150 | °C |

The module typically features a simple 9-pin interface for easy integration.

Remember to respect the BTL output configuration, keep the supply voltage below 5.5V, and provide adequate decoupling. With these precautions, the HW-104 delivers clean, efficient audio amplification for countless DIY applications.

Greater than 90% at full power, eliminating the need for bulky external heatsinks. Load Impedance Compatible: 4Ω to 8Ω audio speakers. Signal-to-Noise Ratio (SNR): for clear background suppression.

DC 2.5V to 5.5V (Ideal for 5V USB or single-cell Li-ion batteries).

In the world of DIY electronics and audio prototyping, the has become a familiar sight. Often sold as a compact breakout board, this module is widely available through online retailers like Amazon, eBay, and AliExpress. However, finding a centralized, detailed HW-104 amplifier datasheet can be challenging, as the module is frequently rebranded or sold without official documentation from a major semiconductor manufacturer.